Three police officers involved in the investigation to locate missing toddler Madeleine McCann were secretly investigated for alleged misconduct.

The three-year-old went missing from her parents holiday apartment in Portugal in 2007, while on holiday with her parents Gerry and Kate McCann.

An extensive worldwide search took place at the time, as an investigation into her disappearance by Scotland Yard is still ongoing.

A freedom of information request about the case has revealed three of the officers involved in the search for the toddler were investigated for misconduct- but all were later cleared.

A source told The Sun: 'Because the precise details of the allegations aren't made public, it's entirely possible good officers have been subjected to a complaints process even though there may be little merit in the allegations against them.'

Madeleine McCann in an Everton Football shirt. The toddler disappeared in 2007 while on holiday with her parents

The parents of the missing girl Maddie, Kate and Gerry McCann, pictured at a hotel in Hamburg, Germany in September 2011

The trio of Met Police officers were accused of 'neglect or failure in their duty' while working on the extensive £12 million investigation.

Two of the allegations not upheld and the other was withdrawn.

On May 3 2007, Gerry and Kate McCann left Maddie asleep in their hotel apartment in Praia da Luz, Portugal as they ate with friends at a nearby restaurant.

A search immediately gets under way and the McCanns meet the Pope in Rome to bring worldwide attention to the search for their daughter.